Volga State University of Water Transport (VGUWT) is a Russian educational institution funded by the Federal Agency for Maritime and River Transportation. It is the largest educational institution in the Volga-Vyatka region. At the beginning of 2010, more than 18,000 students and cadets were enrolled. Since its formation, VGUVT (formerly - VGAWT, GIIVT) has prepared more than 46,000 specialists in their areas..
The article presents the results of an experimental study of heat dissipation and friction in a cylindrical pipe simulating the combustion chamber of a gas turbine engine. The experiments were carried out on a gas-dynamic stand, which is an open-type aerodynamic circuit. Plasmatron made according to single-chamber scheme is used as heat generator. Simulation of the starting mode was carried out by turning on the plasmatron, which allows for a short period of time to obtain high degrees of heating of the gas stream to an enthalpy factor of 0.25. A sharp increase in the flow temperature to 12,000 K/s is accompanied by a corresponding change in the density and viscosity of the working fluid and, as a result, an increase in its speed to 700 m/s2. The time derivatives of temperature and flow rates determine the presence of thermal and hydrodynamic unsteadiness effects under conditions of substantial non-isothermality. In the considered thermogasdynamic situation, conditions are thus formed under which the intensity of heat transfer decreases. The processing of experimental data made it possible to determine the threshold beyond which the efficiency of heat dissipation begins to decrease. This process is facilitated by the dynamics of the process of increasing the temperature of the stream, starting from a threshold of 3000 K/s or more.
According to Goldratt's theory of constraints, it is proved that the capacity of the water transportation system for the European part of Russia is determined by the capacity of the locks of the cascade of reservoirs on the Volga River from Yaroslavl to Astrakhan, on the Kama River from Perm to the Kama Estuary. When forming a cargo transportation scheme, a solution of multi-section pushed trains is proposed, ensuring maximum use of the lock chamber space and compliance with the approach schedule to the gateway, accordingly, minimizing fleet downtime while waiting. The solution to the problem is the formation of regular container lines of barge-tow trains, a method is proposed for dividing the waterway into sections connected through the raids of nodal ports and the raid of the reformation of trains. The rational way of servicing non-self-propelled cargo vessels is determined by the choice of the form of tonnage traction for the main transportation routes, the type of tonnage traction maintenance – route or section, in which the expediency of routes and usage patterns are determined by the technology of combined shipments. The increase in productivity and carrying capacity of the fleet is achieved by eliminating the waiting time for the pusher tug to complete loading and unloading operations and the waiting time for the pushers to arrive at each other. Similarly, the formation of container lines is considered as a prerequisite for the connectivity of each port of departure with each port of arrival. Compliance with the schedule requires the use of regulation of the vessel's speed regime. The article discusses the generally accepted option of adjusting the time through additional stops. The travel time with cargo is calculated according to the rational and economical speed of movement, and the lock-in time does not include waiting time, since the arrival of the train takes place at a pre-agreed time.
The article presents the results of a desk study of the material and technical base of a number of ship repair enterprises of various types performing repair and maintenance of inland and mixed (river-sea) navigation vessels. The study sample includes 150 enterprises of various types that have recognition from the Russian Maritime Register of Shipping for performing the relevant types of work. Based on the analysis of data obtained through a survey, as well as through the analysis of information provided in open sources, a quantitative assessment was carried out regarding the equipment of the material and technical base, the prevalence of the main types of ship repair work, the applied methods of defect detection of ship elements, the available types of ship lifting facilities, and specialized production facilities. A number of deficits hindering the development of the industry have been identified. Among them are a pronounced shortage of ship lifting facilities (less than 23% of the enterprises under consideration have docks, caissons or slipways), the obsolescence of the material and technical base, and low availability of technologies for enterprises to perform repair of new vessels, including repair of hulls made of composite materials, as well as maintenance and repair of engines running on alternative fuels. The necessity for further expansion of the research field and the organization of systematic monitoring of the production capabilities of domestic enterprises is substantiated. Based on the identified features of the development of the ship repair production base, a number of directions for the development of domestic ship repair are proposed. This material has been prepared as part of a research project on the formation of the Fleet-Service-Ship Repair information technology platform for inland and river-sea navigation vessels.
The share of diesel-generator sets (DGS) in Russia's electricity generation capacity is 12 GW, which is approximately 5% of the country's total electricity generation. In our country's small-scale energy sector, especially in regions that are not connected to centralized electricity supply, DGS are the primary sources of electricity. Research on the development of energy-efficient diesel-generator power plants is a current and relevant area in the small-scale energy sector. Diesel-generator power plants are widely used in various technological facilities, including in the maritime industry. To improve the efficiency of this type of power plant by reducing the consumption of hydrocarbon fuel in the production of electricity, a class of DGS with forced regulation of the rotational speed of the internal combustion engines has been developed. Such generator sets have an almost constant specific fuel consumption, even in partial load modes, which means they are highly energy-efficient. These power plants can be built from scratch or by upgrading existing power plants. Currently, most diesel power plants are constant-speed (classic) units with synchronous generators. However, there are alternative generator options available for these power plants, such as asynchronous generators. The advantage of an asynchronous machine with a squirrel-cage rotor is its simple design, mechanical strength, ability to operate at high speeds, and low cost. The use of asynchronous machines in electrical systems is usually associated with the motor mode due to the inability to generate reactive power independently. The use of modern semiconductor converters in autonomous power plants allows for the creation of autonomous generation systems based on asynchronous electric machines.
Использование крупнотоннажных речных катамаранных паромов может существенно повысить эффективность внутреннего водного транспорта за счет увеличения скорости судов. Однако, повышение скорости приводит к увеличению высот корабельных волн, что отрицательно сказывается на гидродинамических характеристиках самого судна, на экологическом состоянии водных объектов, гидротехнических сооружениях. В настоящей работе представлены результаты исследования гидродинамики катамаранов численными методами для FrL=0,181-0,353, который характеризуется большой амплитудой колебаний коэффициентов сопротивления для катамаранов с L=112, L=132 и L=152 м, при ширине одного корпуса 9 и 10 метров с относительным клиренсом от 0,3 до 0,56 для плоского, симметричного и несимметричного (0,35/0,65) внутреннего борта. Использовался программный комплекс NUMECA/FineMarineTM. Результаты позволяют утверждать, что для речных катамаранов при длинах от 112 до 152 м в диапазоне FrL=0,181-0,353 существуют комбинации формы внутреннего борта и длины судна, горизонтального клиренса и скорости движения, при которых будет наблюдаться уменьшение коэффициента сопротивления, обусловленные процессами трансформации волн (интерференции, дифракции, отражения и преломления) в междукорпусном пространстве катамарана. Локальные минимумы сопротивления в окрестности значений около FrL=0,24 и FrL=0,27 для симметричного и несимметричного корпусов отвечают соответственно двум и трем значениям длин поперечных (“кормовых”) волн укладывающихся на длине корпусов. Волны, возбуждаемые источником вблизи носа судна, частично интерферируют с волнами, возбуждаемые кормовой частью судна, учитывая, что кормовой источник находится в противофазе с носовым. The use of large-tonnage river catamaran ferries can significantly enhance the efficiency of inland waterway transport by increasing vessel speeds. However, higher speeds lead to increased ship-generated wave heights, which adversely affect the hydrodynamic performance of the vessel itself, the ecological state of water bodies, and hydraulic structures. This paper presents the results of a numerical study of catamaran hydrodynamics for length-based Froude numbers ranging from 0.181 to 0.353. This range is characterized by large-amplitude fluctuations in the resistance coefficients for catamarans with lengths of 112, 132, and 152 m, a demihull beam of 9 and 10 m, and a relative demihull clearance (gap ratio) from 0.3 to 0.56. The configurations analyzed feature flat, symmetric, and asymmetric (0.35/0.65) inner hull sides. The simulations were performed using the NUMECA/FineMarine™ software package. The results demonstrate that for river catamarans with lengths from 112 to 152 m in the FrL=0.181–0.353, there exist specific combinations of inner hull shape, vessel length, horizontal clearance, and speed that yield a reduction in the resistance coefficient. This reduction is driven by wave transformation processes (interference, diffraction, reflection, and refraction) within the inter-hull space of the catamaran. Local resistance minimum in the vicinity of FrL≈0.24and FrL≈0.27 for symmetric and asymmetric demihulls correspond, respectively, to two and three transverse (stern) wave lengths fitting along the hull length. The waves generated by a wave-making source near the bow partially interfere with the waves generated by the stern, given that the stern wave source is in anti-phase with the bow source.
